IRVINE, Calif. - When he added a sixth in Saturday's 100-meter backstroke to his seventh in the 100 freestyle and second in the 100 butterfly, the greatest swimmer in history summed up his U.S. Championships with some acerbic but lighthearted self-criticism.

"Stellar performance," Michael Phelps said, referring to the backstroke final in which he finished more than a second behind Matt Grevers.

It was the third event here in which Phelps swam well in morning heats but was poor in the evening final.

So he was asked if the problem at this point in his comeback was putting two good races together.

"I think it's getting one solid race together," he said.

Then he proceeded to explain why the second race has been difficult.

"I guess that’s one thing I have had trouble with," he said. "In the morning I’ve been super relaxed. . .It’s just knowing that I haven’t done all the work."

Phelps was unsure whether he would race the 200 individual medley Sunday or use the day to train. He assumed coach Bob Bowman would want him to race because he hasn't done many races that long this season.

"This is probably a better learning experience for me than anything else," he said. "I hate this. (I will do) anything to be able to change this. Little things like this making me feel how I feel will end up playing a big role in what’s going to happen over the next couple years."

Phelps insisted that the results were not planting the seeds of doubt in his mind.

"Whatever I really put my mind to, I know I can accomplish," he said. "I’m not going to use the excuse of taking off a year and a half. When there are workouts, I need to beat everyone, and that’s the bottom line."

He finished with final quip to the question of whether he felt he was getting better every day.